Epidemiologic study of Giardia sp. infection in dairy cattle in southeastern New York State

To identify animal and management factors associated with the risk of Giardia sp. infection in dairy cattle in southeastern New York State, an observational analytical epidemiologic study was conducted. A random sample of 2943 animals in 109 dairy herds located in five counties of southeastern New York was selected from the target population. Fecal samples were collected from animals in the study population and examined for the presence of Giardia sp. using a quantitative centrifugation concentration flotation technique. Data on each animal, and on general management, maternity, preweaning, and postweaning practices were collected by personal interview with the farmer or farm manager. The significance of association of these factors, within each management practice group, with the risk of infection was evaluated using the logistic regression analysis. Weighted indices for each of these four groups were developed, and were evaluated together with the age of the animal and season of sampling for their significance of association with the risk of infection using mixed effect logistic regression analysis. Only the maternity management practices, age of the animal, and the season of sampling were significantly associated with the risk of infection with Giardia sp. Summer housing of bred heifers, on pasture or in tie stalls, was associated with increased risk of infection. Calves that were fed fresh colostrum or separated immediately after birth from the dam were at decreased risk of infection. The risk of infection decreased with the age of the animal and varied by the season of sampling. There was no significant extra binomial variation in the risk of infection in this data. If consideration is to be given to reducing the risk of infection with this parasite, management must be a top priority, especially in younger animals.     

Vaccination studies for the control of campylobacteriosis in Jamaican cattle

Following the first diagnosis of campylobacteriosis in Jamaican cattle a field study was undertaken to determine the pathogenicity of Campylobacter fetus subspecies venerealis Jam (Jamaican strain) and to evaluate the effectiveness of vaccination in controlling the disease. A total of 46 nonpregnant yearling heifers and four two-year-old bulls were used in two separate experiments. The results showed that C fetus subspecies venerealis Jam readily colonised the reproductive tract of susceptible heifers and persisted in some animals (68 per cent of unvaccinated and 33 per cent of vaccinated animals) for the duration of the experiment. Pregnancy was confirmed in 13 of 18 (72 per cent) culture-negative heifers but in only eight of 28 (29 per cent) of the heifers with two or more positive cultures. Vaccination appeared to be curative because 44 per cent of vaccinated heifers were cleared of infection whereas 85 per cent of unvaccinated, inoculated heifers remained infected for at least 17 weeks. Vaccination improved the fertility level of the infected heifers threefold. Infection was not established in vaccinated bulls used for breeding infected heifers.     

The WC1(+) gammadelta T-cell population in cattle: a possible role in resistance to intracellular infection

Intracellular infections are important in veterinary medicine and detailed understanding of the associated immune responses is needed for optimal development of strategies based on diagnosis and vaccination. It is generally accepted that cell-mediated immune responses are of greatest importance in intracellular infections and recent studies from several bovine models of infection indicate that WC1(+) gammadelta T-cells have a number of possible levels of involvement, which remain incompletely defined. Investigations of experimental infection with Mycobacterium bovis in cattle have indicated that WC1(+) gammadelta T-cells are among the first cells to accumulate at initial sites of infection, an observation which has been linked with decreased numbers of these cells in the circulation within days of infection. These WC1(+) gammadelta T-cells have been shown to respond in vitro, both to protein antigens and to non-protein, phosphate containing antigens of M. bovis and to be capable of producing IFN-gamma. Studies of M. bovis infection in calves depleted of WC1(+) gammadelta T-cells by monoclonal antibody have suggested that the presence of these cells is associated with development of a Th1-biased acquired immune response. In combination, these observations allow speculation regarding a possible role for WC1(+) gammadelta T-cells as a link between the innate and acquired immune systems which is instrumental in establishing an appropriate response.     

Paratuberculosis in sheep: its possible role in the epidemiology of paratuberculosis in cattle

A total of 50 sheep originating from 15 Dutch farms with a known paratuberculosis infection in their cattle herd, but with no history of paratuberculosis infection in their sheep flock, were examined for infection with Mycobacterium avium subsp. paratuberculosis (Map). The sheep had been grazing on the same pastures as the cattle or on pastures fertilised with manure from these cows. The sheep were screened for paratuberculosis by serum biochemistry, serology and intradermal skin tests. At necropsy they were examined macroscopically, microscopically and bacteriologically for paratuberculosis.From 10 sheep, originating from eight flocks, Map could be isolated from various tissues but not from the intestinal contents, after an incubation period of 2.5-4 months. Six of these culture-positive sheep had no macroscopic signs of paratuberculosis at necropsy. Seven sheep were Map culture negative but showed macroscopic and microscopic lesions consistent with a paratuberculosis infection. Results of serology and skin tests did not correlate with the results of bacteriological culture. Serum concentrations of calcium, albumin and total protein of the infected, suspected and negative sheep were not different. These results indicate that a substantial number of the sheep examined were infected with Map. Even though this bacterium was not isolated from their faeces, the possibility that these sheep could have been shedding Map with their faeces below detection level or at a later stage of the disease cannot be eliminated. Map infected sheep should, therefore, be considered as a possible factor in the epidemiology of with Map infected cattle herds in The Netherlands. At necropsy bacteriological culture of Map should be performed on a routine basis to improve the diagnosis of paratuberculosis in sheep.     

Citrinin as a possible cause of the pruritis, pyrexia, haemorrhagic syndrome in cattle

An outbreak of the pruritis, pyrexia, haemorrhagic syndrome affected eight of a herd of 175 cows which was divided into two groups of 115 and 60 according to yield. There was no difference in management between them but citrus pulp pellets were fed only to the larger group in which the eight cows were affected. Silage, which had been made without the use of additives, was also fed to both groups. The citrus pulp was visibly mouldy and contained 30 to 40 parts per billion of citrinin. Signs of the syndrome occurred within three days of the cows starting to ingest the citrus pulp, which was fed for 21 days, and the last case occurred six days after the feeding of citrus pulp ceased. Five calves whose dams had been fed citrus pulp were subsequently born with superior prognathism. In contrast to the eight cows that developed the syndrome only one out of 68 heifers which were fed larger quantities of citrus pulp for 10 days developed mild signs of the syndrome and then recovered, suggesting that older animals may be more susceptible. The clinical signs, gross pathology and histopathology are described and compared with those of previous outbreaks. Mycotoxins, particularly citrinin, were strongly implicated as the cause of this outbreak.     

Bartonella spp infection as a possible cause of uveitis in a cat

A 6-year-old castrated mixed-breed cat was evaluated because of unilateral anterior uveitis. The cat was seronegative for antibodies to Toxoplasma gondii, coronaviruses, and feline immunodeficiency virus, and antigens for FeLV p27 and Cryptococcus neoformans. Antibodies to Bartonella spp were detected in serum and aqueous humor. The antibody coefficient (C value) for IgG antibodies to Bartonella spp in the aqueous humor was 4.42; values > 1 suggest ocular production of antibodies and supports a diagnosis of ocular infection. Topical administration of prednisolone and oral administration of prednisone failed to induce a response; however, the uveitis resolved rapidly after the cat was given doxycycline orally. Clinical or laboratory evidence of immunodeficiency in this cat was not detected. Detection of a serum IgG antibody titer to Bartonella spp and ocular production of IgG antibodies to Bartonella spp, exclusion of other causes of uveitis, and response to doxycycline suggests that the cat may have had bartonellosis resulting in uveal tract inflammation.     

Significance of milk as a possible source of infection for human yersiniosis I. Incidence of Yersinia organisms in raw milk in Shimane Prefecture,Japan

Twelve strains of Yersinia enterocoliticaa and 4 strains of a Y. enterocolittica-like organism (Y. intermedia) were isolated from 374 pooled raw milk samples. Growth occurred in a cold enrichment system using phosphate buffer solution (7 strains), peptone solution (5 strains) and yeast extract—casein—cystine broth (5 strains) Serovar 13,7 was most frequently isolated (8 strains) followed by serovars 5,27 (2 strains), 6,31, 7,8, 14 and 22 (each one strain). Two strains were untypable, serologically. Seasonal variation was of little consequence, but the regional incidence was an important feature of the bacteriological findings. Autoagglutination tests gave negative results with all isolates. Although so-called “clinical strains” were not identified, the relationship of the strains of Yersinia to milk-borne infections in humans cannot be excluded.     

Plasma prolidase activity as a possible diagnostic index of chronic hepatic abscess in cattle

The usefulness of prolidase as a biochemical parameter to represent the chronic state of hepatic abscess was discussed in eight cattle experimentally inoculated with Fusobacterium necrophorum and 18 spontaneously affected cattle. Blood was daily collected to measure the plasma prolidase activity and sialic acid level from the experimental cattle for 90 days after inoculation. In three out of four cattle affected with hepatic abscess, prolidase activity began to rise about 40 days after inoculation, and maintained high activity till 90 days. In the same cattle the sialic acid concentration increased from 7 to 10 days after inoculation, and gradually returned to the normal value 50 days after it. Another cow showed a similar change in early stage of experiment, but prolidase activity decreased after 70 days and sialic acid concentration maintained high level till 90 days. In two cattle, which showed scars but no abscess on autopsy, the prolidase activity increased temporarily from 40 to 55 days after inoculation. In the control cattle inoculated with an inactivated bacterial suspension, neither the sialic acid level nor the prolidase activity showed any large variation in the experimental period. Among the spontaneously affected cattle, those with a high sialic acid level revealed normal prolidase activity and those with a normal sialic acid level had high prolidase activity.     

Campylobacter jejuni infection in the ferret: an animal model of human campylobacteriosis

Campylobacter infection in weanling ferrets (Mustela putorius furo) was studied as an animal model for enteric campylobacteriosis in persons. The screening of fecal cultures on selective campylobacter media showed that Campylobacter jejuni/coli was not present in the normal enteric flora. Intragastric feeding of a mixture of cat feed and 2.5 X 10(8) C jejuni isolated from ferrets with naturally occurring proliferative colitis was accomplished. All ferrets (n = 8) became infected on 3 days after they were inoculated, and at 5 to 7 days, they had bile-tinged, liquid feces with excessive mucus and blood. Ferrets gradually recovered from the diarrhea, and feces were normal 10 to 14 days after inoculation was done. Feces contained C jejuni at 14, 23, 28, 39, 46, 60, 91, 101, 109 and 144 days. In the second experiment, weanling ferrets initially were treated with 10% sodium bicarbonate, and 1 X 10(10) C jejuni organisms were administered in the cat feed. Diarrhea with fecal leukocytes and occult blood with occasional mucus appeared in almost all of the 21 ferrets from days 4 through 7. Campylobacter jejuni was isolated from the blood of 11 ferrets between 3 hours and 14 days after they were inoculated. Campylobacter jejuni bactericidal antibodies were present in serum samples at 14 days, with titers of 1:16 to 1:32. Intestinal lesions including cellular infiltration with mononuclear and polymorphonuclear leukocytes were in the lamina propria of the pyloric mucosa and small intestine of infected and control ferrets. The colon of 3 infected ferrets had small focal infiltrates of neutrophils on the lamina propria; one ferret had perivascular cuffing.(ABSTRACT TRUNCATED AT 250 WORDS)     

The prevalence of bovine venereal campylobacteriosis in cattle herds in the Lake Chad basin of Nigeria

The prevalence of bovine venereal campylobacteriosis (BVC) was investigated in the Lake Chad basin of Nigeria. Preputial washings and cervico-vaginal mucus samples were obtained from 270 cattle presenting a history of abortion and lowered fertility, kept in traditional and institutional farms. All the samples investigated were cultured using standard bacteriological technique. Campylobacter fetus was isolated from six bulls and four cows. In all cattle sampled, the isolation rates were 2.2% for C. fetus subsp. venerealis and 1.5% for C. fetus subsp. fetus; the herd and within-herd prevalence rates for C. fetus were 22.2% and 3.4%, respectively, while the overall active infectivity rate was 3.7%. BVC probably contributes to lowered fertility and abortions found in cattle in the Lake Chad basin of Nigeria, associated more with C. fetus subsp. venerealis than C. fetus subsp. fetus.     

Insulin-like growth factor-I as a possible hormonal mediator of nutritional regulation of reproduction in cattle

The current review aims to establish insulin-like growth factor-1 (IGF-I) as the factor that signals nutritional status to the reproductive axis, and show that assessment of IGF-I in blood early postpartum during the negative energy balance (NEB) period could be used to predict both nutritional and reproductive status in dairy cattle. The review also explores the effect of nutritional status on circulating IGF-I concentrations and the endocrine role of IGF-I on the reproductive axis. IGF-I plays an important role in gonadotropin-induced folliculogenesis, ovarian steroidogenesis and corpus luteum (CL) function. It also modulates pituitary and hypothalamus function. IGF-I clearly has an endocrine role on the reproductive axis. Severe under nutrition significantly reduces plasma IGF-I concentrations. During the critical period of NEB in high yielding dairy cattle early postpartum, IGF-I concentrations are low in blood and its levels are positively correlated to energy status and reproductive function during this period. Changes in circulating IGF-I immediately postpartum may help predict both nutritional and reproductive status in dairy cattle. IGF-I is therefore one of the long sought factors that signal nutritional status to the reproductive axis.     

Neospora-like protozoan infection as a major cause of abortion in California dairy cattle

Ninety-five aborted bovine fetuses received from California dairies over a 4.5-year period had histologic lesions of focal encephalitis. Protozoa that reacted with Neospora caninum antiserum were detected in the brain of 88 of these fetuses and in the heart of 1 fetus. Sarcocystis spp schizonts were seen in the vascular endothelium of 1 fetus. It was concluded that a Neospora-like cyst-forming coccidian may be a major cause of abortion in California dairy cattle.     

Torque teno virus infection in the pig and its potential role as a model of human infection

Torque teno viruses (TTVs), of the genus Anellovirus, are single-stranded circular DNA viruses that infect many vertebrate species. Although viruses of this type have quite a stable genome, they exhibit low nucleotide homology. Torque teno virus infection has not been consistently linked to specific diseases, although there is epidemiological evidence of an association with disease in humans. The recent recognition of naturally occurring TTV infection in swine and its epidemiological resemblance to human TTV raises the possibility of using the pig as a model to study human TTV infection. Such an approach will require the development of novel investigative tools to study the epidemiology, transmission, immune responses and potential pathogenesis of TTV infection. The present review summarises research on animal TTV infection, focussing in particular on TTV infection in the pig, and considers how a porcine experimental infection model might assist in the study of human TTV infection.     

Comparative study of milk compositions of cattle,sheep and goats in Nigeria

Variations in the milk composition of Nigerian cattle, sheep and goats (Bunaji, Yankasa and Red Sokoto breeds, respectively), as well as residual phenotypic correlations between the milk constituents, were investigated. Results indicated that sheep and goats differed significantly (P < 0.05) from cattle in all constituents except protein percentage, which averaged 5.43%, 5.43% and 5.49%, respectively. Caprine milk contained the highest percentages of fat (5.80%), total solids (15.37%) and ash (0.77%), and bovine milk contained the least percentages of fat (0.68%) and lactose (1.84%). Overall, the milk compositions of sheep and goats were very similar as they were not statistically different from each other (P > 0.05). Residual phenotypic correlations between the milk constituents revealed highly significant (P < 0.01) and positive relationships between total solids and solids‐not‐fat (0.97 and 0.98 in cattle and sheep, respectively). All other correlations were positive in cattle (ranging from 0.12 to 0.77), except between protein and total solids (?0.44) and protein and solids‐not‐fat (?0.64). Multiple linear regression equations were fitted to predict the percentages of protein and fat. It was demonstrated that the protein percentage could be predicted from total solids and solids‐not‐fat with the highest accuracy of 94%, 86% and 82% in cattle, sheep and goats, respectively. On the other hand, the accuracy of prediction of fat percentage was very low in all the species (R² = 0.01, 0.3 and 0.37 in cattle, sheep and goats, respectively).